Azacytidine has been shown to be active in acute non lymphocytic leukemia (ANLL). Pyrazofurin augments the activity of azacytidine biochemically therefore the combination of pyrazofurin plus azacytidine has been employed in 15 adult ANLL patients and 1 patient with CML in blast crises. Two patients achieved a CR days and 1 a PR. The combination has significant toxicity especially myelosuppression and skin rashes. Additional patients are being entered to further define the antileukemia activity of this combination. AMSA has recently completed phase I studies with some suggestion of anti-leukemic activity. Therefore AMSA2 has been given to 10 ANLL and 4 ALL adult patients at doses of 150-500 mg/m squared as a single dose every 1-3 weeks. No remissions have been observed. Dose limiting toxicity has not been reached in this population. Additional patients are being entered to further define toxicities and the antileukemic activity of this new drug. *